Monochrome 1-bit image parsing
When I tried to use Arduino to make a simple game for TV Sayzo. There was need to parse 1-bit data from bitmap (*.bmp) image to bytes for input to C.
I haven’t found anything suitable on the web that time (2014?). I made decision to write my own utility, which recently I have upgraded code of it.
BMP format
Actually, the BMP format is very simple; it consists of 2 parts: a header with metadata and actual bytes without any compression.
Header
| Bytes | Value/Type | |
|---|---|---|
| 2 bytes | 0x4D42 | BMP format identifier |
| 4 bytes | uint32_t | File size in bytes |
| 2 bytes | int16_t | not in use/reserved |
| 2 bytes | int16_t | not in use/reserved |
| 4 bytes | uint32_t | Offset to image data in bytes from beginning of file |
| 4 bytes | uint32_t | DIB Header size in bytes |
| 4 bytes | int32_t | Width of the image |
| 4 bytes | int32_t | Height of the image |
| 2 bytes | uint16_t | Number of color planes |
| 2 bytes | uint16_t | Bits per pixel |
| 4 bytes | uint32_t | Compression type |
| 4 bytes | uint32_t | Image size in bytes |
| 4 bytes | int32_t | Pixels per meter (X) |
| 4 bytes | int32_t | Pixels per meter (Y) |
| 4 bytes | uint32_t | Number of colors |
| 4 bytes | uint32_t | Important colors |
Data
After the header data, follow plain data in bytes as unit8_t or unsigned char. This makes parsing extremely easy.
Check bmp2bytes to parse the 1-bit images and get image data and header.
Example
bmp2bytes -f "0x%x" -d "," -n ./tests/girl.bmp
Example of output
0xff,0xfe,0x0,0x0,0x5f,0xff,0xff,0x6a,0x80,0x0,0x0,0x7f,0xfa,0xaa,0xad,0xdd,0xfd,0x0,0x0,0x35,0xbb,0xb5,0xb5,0x0,0x0,0x0,0x7f,0x7f,0x55,0x55,0xff,0xef,0x0,0x0,0x3f,0xdd,0xff,0x5a,0x60,0x0,0x0,0x3b,0xea,0xd6,0xd6,0x7f,0x7e,0x0,0x0,0x55,0xff,0xad,0xef,0x80,0x0,0x0,0x3f,0xfd,0x52,0x5b,0xdb,0xfd,0x0,0x0,0x7e,0xdd,0xf6,0xb2,0xe0,0x0,0x0,0x3b,0xfe,0xbb,0x4d,0xff,0xee,0x0,0x0,0xb7,0xff,0xbf,0xdf,0x10,0x0,0x0,0x7e,0xdd,0x4d,0xb6,0xef,0xfc,0x0,0x0,0x5f,0x6d,0xfd,0x74,0xe0,0x0,0x0,0x2f,0xf7,0xb4,0xa9,0xfd,0xfc,0x0,0x0,0xf7,0xff,0xdf,0xde,0x90,0x0,0x0,0x3f,0xfa,0xa6,0x6d,0xff,0xfc,0x0,0x0,0xbf,0xfd,0xf7,0xf7,0x50,0x0,0x0,0x37,0xbf,0x57,0x56,0xfe,0xdc,0x0,0x1,0x7e,0xef,0xfd,0x5d,0xc0,0x0,0x0,0x3e,0xfa,0xb2,0xb6,0xdf,0xfc,0x0,0x0,0xf1,0xbf,0xaf,0xff,0x58,0x0,0x0,0x3f,0xed,0x4d,0x4d,0xef,0xf4,0x0,0x1,0x0,0x15,0xfb,0xb5,0x40,0x0,0x0,0x16,0xfd,0xd5,0xb5,0xff,0xf8,0x0,0x0,0xfa,0x1,0x7d,0xdf,0xf8,0x0,0x0,0x7f,0xde,0x4a,0x96,0xfb,0xf8,0x0,0x1,0x7f,0x80,0x6f,0xfa,0xa0,0x0,0x0,0x36,0xfb,0x75,0x6b,0xff,0xb8,0x0,0x0,0xd4,0x68,0x1a,0x6f,0x0,0x0,0x0,0x3f,0x6a,0x8a,0xdc,0x7d,0xf8,0x0,0x0,0x40,0x3,0x2f,0xb0,0x0,0x0,0x0,0x17,0xfa,0xea,0x47,0xdf,0xf8,0x0,0x4,0x40,0x1,0xf7,0xb0,0x0,0x0,0x0,0x7a,0xdd,0x2a,0xb2,0xff,0xd0,0x0,0x1,0x0,0x0,0x5a,0xc8,0xa,0x0,0x0,0xf,0xb6,0xd5,0x5b,0xf7,0x70,0x0,0xc,0x0,0x8,0x2f,0xa8,0x1,0x0,0x0,0x26,0xf9,0x2a,0xa4,0xbf,0xf0,0x0,0x3,0x50,0x0,0x5a,0xa0,0x0,0x0,0x0,0x33,0xde,0x4d,0xb7,0xfb,0xd0,0x0,0x9,0x11,0x0,0x2f,0x80,0x0,0x0,0x0,0x39,0x75,0x64,0xb2,0xff,0x60,0x0,0x2,0xce,0xea,0x9e,0x40,0x10,0x0,0x0,0x15,0xfb,0x16,0xcd,0xaf,0xe0,0x0,0x9,0x6d,0x39,0x6b,0x40,0x0,0x0,0x0,0x1d,0x55,0x69,0x36,0xfb,0xe0,0x2,0x6,0xb7,0xed,0x5f,0xa8,0x0,0x0,0x0,0x15,0x5e,0x96,0x93,0xff,0xe0,0x1,0x1,0x52,0xaa,0xf6,0x85,0x40,0x0,0x0,0xf,0xea,0x92,0xd9,0xdd,0xe0,0x0,0x1a,0xdd,0xf5,0x5f,0x6a,0xa8,0x0,0x0,0x4,0xad,0x69,0x25,0xff,0xa0,0x0,0x1,0x6a,0xaf,0xee,0x91,0x50,0x0,0x0,0x3,0xfa,0x96,0xd6,0xef,0xf0,0x0,0x5,0xaf,0xf7,0x77,0x5b,0x58,0x0,0x0,0x8,0xae,0x52,0x55,0xff,0xe0,0x0,0x0,0xaa,0xbb,0xdd,0x29,0xaa,0x0,0x0,0x4,0xd3,0x5a,0xaa,0xfb,0x70,0x0,0x1,0xa7,0x75,0x77,0x9e,0xd4,0x0,0x0,0x6,0x7c,0x85,0x55,0xdf,0xf0,0x0,0x0,0x59,0xde,0xde,0xa5,0x68,0x0,0x0,0x1,0x8b,0x5a,0xab,0xf7,0xb8,0x0,0x9,0x4d,0xeb,0x7f,0x9b,0x2a,0x0,0x0,0x0,0x69,0x4a,0xa8,0xfb,0xf0,0x0,0x4,0x65,0x6a,0xba,0xcd,0xe8,0x0,0x0,0x1,0x6c,0xaa,0xaf,0xbf,0xf8,0x0,0x2,0x92,0xb5,0xdf,0xa6,0xa8,0x0,0x0,0x0,0xb2,0x49,0x50,0xff,0xb8,0x0,0x1,0x39,0xd9,0x6f,0xad,0xd4,0x0,0x0,0x0,0x4d,0x2a,0xa7,0xf7,0xe8,0x0,0x2,0x8c,0x6d,0xa2,0xaa,0x50,0x0,0x0,0x0,0x32,0x8a,0xb2,0xff,0xf8,0x0,0x2,0xb2,0x54,0xa,0x97,0xa8,0x0,0x0,0x0,0x1d,0x65,0x9a,0xf5,0x78,0x0,0x1,0x1d,0x2a,0xa,0x29,0x50,0x0,0x0,0x0,0x2a,0x94,0x65,0xbf,0xdc,0x0,0x12,0xab,0xd5,0x74,0x16,0xa4,0x0,0x0,0x0,0x8,0xa9,0xaa,0xff,0xfc,0x0,0x1,0xaa,0x5a,0x93,0x4a,0xa0,0x0,0x0,0x0,0x6,0x26,0x95,0xff,0xd8,0x0,0x10,0xbf,0x6a,0x98,0x6b,0x20,0x0,0x0,0x0,0x1,0x10,0xc5,0xad,0xfc,0x0,0x1,0xc9,0xb7,0x67,0x24,0x90,0x0,0x0,0x0,0xa,0xca,0x34,0xff,0x7e,0x0,0x0,0x66,0x58,0x95,0x5a,0xd0,0x0,0x0,0x0,0x3,0x2a,0xc9,0xff,0xbe,0x0,0x10,0x73,0x48,0x0,0x4b,0x0,0x0,0x0,0x0,0x1,0xa2,0x4a,0xb7,0xde,0x0,0x10,0x35,0x80,0x1,0x29,0xd0,0x0,0x0,0x0,0x1,0x51,0x49,0xff,0xed,0x0,0x18,0x5a,0x0,0x0,0x4,0x20,0x0,0x0,0x0,0x1,0x5c,0x24,0xfd,0xff,0x0,0xc,0x2d,0x60,0x0,0xb,0x80,0x0,0x0,0x0,0x0,0xa1,0x55,0xde,0xf7,0x0,0xc,0x16,0xb4,0x80,0x0,0x80,0x0,0x0,0x0,0x0,0x54,0x82,0xff,0x7d,0x0,0xe,0xa,0x92,0xa4,0x1a,0x80,0x0,0x0,0x0,0x0,0x52,0x51,0xeb,0xdf,0x80,0xb,0x5,0x68,0x10,0x22,0x0,0x0,0x0,0x0,0x0,0x9,0x2c,0xff,0x77,0x0,0x16,0x85,0xb5,0x44,0x8c,0x0,0x0,0x0,0x0,0x0,0x6,0x42,0x7f,0xfb,0x80,0xb,0xc0,0xdd,0x42,0x62,0x0,0x0,0x0,0x0,0x0,0x1,0x22,0xfb,0xfe,0x0,0x1a,0xa2,0x55,0x6b,0x10,0x0,0x0,0x0,0x0,0x0,0x0,0x11,0xaf,0x6b,0x0,0x16,0xf0,0xaf,0xb4,0xa0,0x0,0x0,0x0,0x0,0x0,0x0,0x5,0xfd,0xf4,0x0,0x4d,0xd8,0x29,0x4d,0x40,0x0,0x0,0x0,0x0,0x0,0x1,0x40,0xef,0x50,0x3,0x2b,0x6c,0x25,0x65,0x40,0x0,0x0,0x0,0x0,0x1,0x10,0x30,0xf5,0x0,0x1,0x2d,0x77,0x15,0x34,0x0,0x0,0x0,0x0,0x0,0x0,0x88,0xa,0xbc,0x0,0x1,0x57,0xad,0x82,0xca,0x0,0x0,0x0,0x0,0x0,0x1,0xa6,0x9,0x6a,0x0,0x0,0x9a,0xf6,0xa0,0x10,0x0,0x0,0x0,0x0,0x0,0x0,0x50,0x82,0xad,0x80,0x0,0x5f,0x5a,0xd8,0x0,0x0,0x0,0x0,0x0,0x0,0x1,0x16,0x52,0xf4,0x80,0x0,0x2b,0x6e,0xea,0x0,0x0,0x0,0x0,0x0,0x0,0x1,0x52,0xba,0xd8,0xc0,0x0,0x17,0xfb,0x2d,0xa0,0x0,0x0,0x0,0x0,0x0,0x0,0x98,0xdd,0xf9,0x60,0x0,0x1e,0x95,0xd5,0x50,0x0,0x0,0x0,0x0,0x0,0x0,0x66,0x67,0xfd,0xe0,0x0,0xb,0xfd,0x75,0xd0,0x0,0x0,0x0,0x0,0x0,0x0,0x1b,0x3d,0xff,0xe0,0x0,0x2d,0xaf,0x5a,0x40,0x0,0x0,0x0,0x0,0x0,0x0,0x69,0x4d,0xf9,0xa0,0x0,0xf,0x7b,0xef,0xa0,0x0,0x0,0x0,0x0,0x0,0x0,0x15,0x36,0xfd,0xf0,0x0,0x5,0xf6,0xa9,0x40,0x0,0x0,0x0,0x0,0x0,0x0,0x2a,0x95,0xfd,0xd0,0x0,0x2,0xda,0xee,0xa0,0x0,0x0,0x0,0x0,0x0,0x0,0x14,0x8a,0xfe,0xf0,0x0,0x1,0x7d,0x76,0x80,0x0,0x0,0x0,0x0,0x0,0x0,0xa,0x4b,0xfe,0xd0,0x0,0x1,0x56,0xab,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x5,0x28,0xfc,0xe8,0x0,0x0,0xb9,0x6e,0x80,0x0,0x0,0x0,0x0,0x0,0x0,0x2,0xcb,0xfe,0x78,0x0,0x0,0xd,0x32,0x80,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x64,0xff,0x78,0x0,0x0,0x2a,0xae,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x5,0x35,0xff,0x30,0x0,0x0,0x1,0x59,0x0,0x0,0x0,0x0,0x0,0x0,0x1,0x40,0x4a,0xff,0xb8,0x0,0x0,0x14,0xa6,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x11,0xff,0xdc,0x0,0x0,0x2,0x29,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x40,0x8c,0xff,0xdc,0x0,0x0,0x1,0x14,0x80,0x0,0x0,0x0,0x0,0x0,0x0,0x10,0x2,0xff,0x9a,0x0,0x0,0x0,0x8a,0x0,0x0,0x40,0x0,0x0,0x0,0x0,0x0,0x48,0xff,0xc6,0x0,0x0,0x2,0x28,0x0,0x0,0x80,0x0,0x0,0x0,0x0,0x10,0x2,0xff,0xf1,0x0,0x0,0x0,0x6,0x80,0x0,0xc0,0x0,0x0,0x0,0x0,0x0,0x0
Creating 1-bit bitmaps
GIMP
- Toolbar > Image > Mode > Index
- File > Export as…
- Save file with extension bmp.
ImageMagick
ImageMagick has an enormous amount of image processing features. It can covert any file to a 1-bit bitmap with a single command:
ImageMagick <7
magick convert -monochrome image.png 1bit.bmp
ImageMagick 7+
magick image.png -monochrome 1bit.bmp
MS Paint and lots of other image editors
Process of creating monochrome images in the most of the image editors is the same. Just set the image to an indexed palette with 2 colors black and white and save.
Feedback
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